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2018 Q50 Red Sport Misfire and Rough Idle - Check Engine Light On

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Tom H. · rep 0 · May 22, 5:04 AM · 1 replies · solved · Question

Vehicle: 2018 Infiniti Q50 Red Sport 400

Hey everyone,

I'm having a persistent issue with my 2018 Infiniti Q50 Red Sport 400. Lately, it's developed a really rough idle, especially when cold, and I've noticed a significant drop in power under acceleration. The check engine light came on a few days ago and hasn't gone off.

I tried checking the gas cap, but that wasn't it. It feels like the engine is struggling, almost like it's skipping a beat. I'm worried it might be something serious with the engine. Has anyone else experienced this with their VR30DDTT engine?

Any ideas on what could be causing this or what I should check before taking it to the dealership? I'm hoping it's something relatively simple.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 5:04 AM

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ClearTheCode admin answer:

It sounds like your 2018 Infiniti Q50 Red Sport 400 is experiencing a common issue related to engine misfires. The rough idle, loss of power, and illuminated Check Engine Light (CEL) are classic symptoms. When the CEL comes on, the car's computer typically stores a Diagnostic Trouble Code (DTC) that can help pinpoint the problem.

1. Get the OBD-II Codes Read: The first step is to get the OBD-II codes read. Most auto parts stores offer this service for free. Common codes for misfires include:

  • P030X: Where 'X' is the cylinder number (e.g., P0301 for cylinder 1 misfire, P0302 for cylinder 2, etc.).
  • P0300: Random/Multiple Cylinder Misfire Detected.

2. Common Causes for Misfires in VR30DDTT Engines:

  • Spark Plugs: Worn or fouled spark plugs are a very common cause of misfires. The VR30DDTT engine can be hard on plugs, especially if tuned or driven aggressively.
  • Ignition Coils: A failing ignition coil for a specific cylinder will cause a misfire in that cylinder.
  • Fuel Injectors: Clogged or faulty fuel injectors can lead to an improper air/fuel mixture, causing a misfire.
  • Vacuum Leaks: Leaks in the intake system can introduce unmetered air, leading to a lean condition and misfires.
  • Low Compression: Less common, but a serious issue like a burnt valve or head gasket problem can cause a misfire due to low compression in a cylinder.

3. When to See a Shop: If the OBD-II codes point to a specific cylinder, you might be able to diagnose and replace spark plugs or ignition coils yourself if you have the tools and experience. However, given the complexity of the VR30DDTT engine and the potential for more serious issues like fuel injector problems or turbocharger-related issues (though less likely for a simple misfire), it's highly recommended to:

  • Visit a qualified Infiniti specialist or dealership: They have the specific diagnostic tools and expertise for your vehicle.
  • Address the issue promptly: Driving with a persistent misfire can lead to further damage, including catalytic converter failure, which is an expensive repair.
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